I have not owned a bike since I was a child but now would like to buy a bike primarily for riding in the nearby park. I know I want a comfort bike which I will probably use for less than 4 hours a week (only on the weekends). My husband would also like to buy a bike for the same reasons. Once we both get comfortable riding alone, he will probably buy a seat for our 2 year old son to ride with him.

What are the best brands for this type of riding. I will go to the local bike store but would like some base knowledge before walking there. I don't want to spend more than $200 per bike.

The brand makes little difference, they are all made in the same factory in Taiwan or China.
Find your local bike shop and look at the brands that they stock. You can chose an appropriate style of bike , probably a "comfort" or "hybrid" style. The comfort style bikes usually have MTB size wheels and the the hybrids have larger diameter wheels. It makes little difference unless you are small, then a small wheel is preferable.
The support you get from your LBS is important. They will ensure that the bike fits you, that it is well assembled and will be on hand to service the bike later.
Make sure that the bike can accept a proper luggage rack that bolts to the frame (for the child seat).
If you want the best value then pick a good time of year (Jan-March), don't worry about getting this years latest model, negotiate on extras such as helmets, repair kits, spares and other accessories, child seats etc rather than cash reduction.
Don't get a bike the wrong size just because it is good value.

Unfortunately $200 seems a bit low for a new bike these days.
Have you thought about possibly buying a couple used bikes or tried searching for a local Bicycle co-op? For example: The co-op in Cleveland sells all brands of used bikes (Trek, Cannondale, Giant, etc.) for less than $200 and the bikes come with a 3-month warrantee period with free maint.
Enjoy

Suggest a bicycle shop for buying a bike. Wall- or K-mart is NOT the place to get service after you buy a bike, but your local bike shop is!
Buy what you can afford and a good used bike from a bike shop should also be considered. Fit/comfort is important!

i never said anything about going to a department store to service a bike. i suggested she go there to buy one, because of her budget and her 4 hours of use per week. and if she reads the thread i linked to, she should be fine.. assuming she takes all their advice about what to look for in a department store bike..